Rafts don't stand up to sharp points very well (i.e. freshly cracked limestone, knives, etc), but otherwise they're incredibly durable. Most anyone here who pushes rubber probably has one or more stories of their boat slamming into rocks, falling off their trailer and sliding down the highway, purposely sliding down a rock face in their raft, or just general wear and tear for 20+ years without failure.
Here's a recent example of what a raft can handle: Rope Wrap: How To—
Search around the site, there have been tons of threads on how to best choose a raft. My own bias for a dialed out fishing rig: a 13' Maravia with a Down River Equipment fishing frame.